US stocks sink; Dow heads for fourth straight loss

Specialist Patrick King, right, works with traders at his post on the floor of the New York Stock Exchange Thursday, March 13, 2014.

Stocks are turning sharply lower in afternoon trading as tensions flare up over Russia's presence in Ukraine.

The Dow Jones industrial average fell 180 points, or 1.1 percent, to 16,163 in as of 1:15 p.m. Thursday. It was down as much as 209. The Dow is headed for its fourth consecutive loss. It's down 290 points so far this week.